In recent years, secondary batteries, which can be charged and discharged, have been widely used as an energy source for wireless mobile devices. In addition, secondary batteries have attracted considerable attention as an energy source for electric vehicles and hybrid electric vehicles, which have been developed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles using fossil fuel. Therefore, secondary batteries are being applied to an increasing number of applications owing to advantages thereof and, in the future, secondary batteries are expected to be applied to even more applications and products.
Based on the construction of electrodes and an electrolytic solution, secondary batteries may be classified into a lithium ion battery, a lithium ion polymer battery, and a lithium polymer battery. In particular, the lithium ion polymer battery has been increasingly used because the lithium ion polymer battery has a low possibility of leakage of an electrolytic solution and can be easily manufactured.
Based on the shape of a battery case, secondary batteries may also be classified into a cylindrical battery having an electrode assembly mounted in a cylindrical metal container, a prismatic battery having an electrode assembly mounted in a prismatic metal container, and a pouch-shaped battery having an electrode assembly mounted in a pouch-shaped case made of an aluminum laminate sheet.
The greatest advantage of a wireless device, such as a laptop computer, is portability, and a secondary battery plays one of the greatest roles in improving the portability of such a wireless device.
The secondary battery is widely used as an energy source for diverse electronic products as well as various kinds of mobile devices. However, various kinds of combustible materials are contained in the secondary battery. As a result, the lithium secondary battery may overheat or explode due to overcharge of the secondary battery, overcurrent in the secondary battery, or external physical impact applied to the secondary battery. In order to solve the above problems, safety elements, such as a positive temperature coefficient (PTC) element and a protection circuit module (PCM), which are capable of effectively controlling an abnormal state of the secondary battery, such as overcharge of the secondary battery or overcurrent in the secondary battery, are connected to a battery cell of the secondary battery.
A battery pack having parts, such as the safety elements and PCM module, loaded in a battery case is manufactured through a somewhat complicated process in which an electrode assembly is mounted in the battery case, an electrolytic solution is injected into the battery case, and the battery case is sealed. A label indicating the specification of the battery pack is attached to the outside of the case.
FIG. 1 is a schematic view showing a conventional battery pack for laptop computers.
Referring to FIG. 1, a battery pack 10 is configured to have a structure in which a battery module including a plurality of batteries connected to each other in series and in parallel is mounted in a pack case 20, the pack case 20 is covered by a cover 30, and a sheet, such as a label sheet 40 indicating the specification of the battery pack, is attached to the outside of the pack case 20.
In the case in which a label sheet is attached to a sheathing case of a secondary battery manually or using a labeling device according to the conventional art, however, jigs or devices for loading the jigs must be exchanged depending on the size of the battery case, whereby productivity is reduced.
In addition, in the case in which a bent portion, a concave portion, or a convex portion is formed at the battery case, a portion of the label sheet or the sheathing sheet is not tightly attached to the battery case. As a result, air bubbles may be formed between the battery case and the label sheet, or the label sheet may be folded, whereby the battery case does not have an aesthetically pleasing appearance.